Bobbit worms are some of the longest of marine worms.
Waiting for their victims to come along, they reach out and grab their hapless victims in the blink of an eye, so fast that they can slice their victims in two!

Segmented worms are extremely mobile and possess strong jaws for hunting and feeding on their prey.
Some worms are covered in hairs for protection scavenging on the sea floor for detritus. While others are delicate fans protected by their self made tubes, which they retreat back into when threatened, these are filter feeders and feed on plankton.